Japanese Laid-open Patent Publication No. 2008-33266 describes, as a technique for reinforcing a spliced portion in which coated optical fibers are connected to each other, a technique using an inner tube for housing a fusion-spliced portion, a rod-shaped high-strength body having a crescent-shaped cross section; and an outer tube covering the inner tube and the high-strength body. In addition, Japanese Laid-open Patent Publication No. 2008-65170 describes a holding member for a fusion-spliced portion capable of fixing an optical drop cable and a fusion-spliced portion of optical fibers exposed from the distal end of the optical drop cable, and an accommodating member for a fusion-spliced portion in which the holding member is housed in a protective member.
Coated optical fibers have low resistance against tensile force. Accordingly, merely extending a reinforcing rod along the fusion-spliced portion and placing a heat shrink tube over the entire fusion-spliced portion to reinforce the fusion-spliced portion does not provide adequate strength against the tensile force in the reinforcing section, and there is a concern that defects will occur in the fusion-spliced portion. When the defects occur in the fusion-spliced portion, the entire installed optical fiber cable must be redrawn, and the optical fiber cable and the operation to wire the cable become inefficient.